The present invention relates to a method and a device for stainless steel production without electrical energy supply on the basis of liquid pig-iron and FeCr solids, wherein, after a pretreatment in a blast furnace and a DDD treatment (dephosphorization, desiliconization, desulpherization) in a DDD installation, the liquid pig-iron is subsequently heated, refined or alloyed in an AOD converter, is reduced and finally an adaptation/adjustment of the treated steel melt is carried out in a ladle furnace.
The use of an AOD converter for manufacturing noble steels is already known. Thus WO 02/075003 describes a control method based on a continuous measurement of exhaust gases in combination with a computer and a dynamic model by means of which the necessary blow rates of oxygen and inert gas as well as the material charges are controlled.
EP 1 310 573 A2 discloses a method for manufacturing a metal melt, particularly for quenching a metal melt for manufacturing, for example, alloyed stainless steel or noble steel in an AOD converter, wherein the method is based on a computer technology which takes place in accordance with a process model and which controls the metallurgical installation, the process model describes the behavior for at least one variable process parameter between a first process value, an adjusting value, and a final process value. An example describes the process sequence for manufacturing a steel of the class AISI 304.
Stainless steels of the ferritic steel group AISI 4xx are conventionally always manufactured from scrap of the same type in the EAF and are later additionally alloyed and decarbonized in the AOD converter. In order to utilize the use of pig-iron, pig-iron pretreated in a steel mill with scrap and alloy melted into the pig-iron is mixed in a ladle outside of the furnace and is then charged into the converter.
WO 2006/050963 A2 proposes a method for producing stainless steel of the ferritic steel group AISI 4xx, particularly the steel group AISI 430, on the basis of liquid pig-iron and FeCr solids, with a DDD process line and the AOD converter with successively carried out method steps:                Pretreatment of the liquid pig-iron in the blast installation and charging of the AOD converter with slag-free liquid pig-iron,        Heating, refining/alloying, and reducing the liquid pig-iron in the AOD converter,        Final adaptation/adjustment of the treated steel melt in the casting ladle.        
In this known method, the manufacture of the stainless steel is carried out advantageously with the use of the AOD converter without the use of an EAF, i.e., without the supply of electrical energy. However, this known method has the disadvantage that finally because of the lack of energy in this method only the manufacture of ferritic steels is possible.